Question about SLAMing

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
stube40
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My Pool: Salt water pool, 27,000 litres, salt water cell chlorinator, sand filter

Question about SLAMing

Postby stube40 » Fri 19 Jan, 2018 04:01

I'm about to SLAM my pool. I'm very new to the process having never done it before. I have a salt-water pool (details in sig), but I think my CYA/stabiliser level is virtually zero (probably not had any added in the last year). I have just received a good 'test-all' kit from Clear Choice Labs. Some questions:

1) Do I try to get the CYA level to some nominal default before I start SLAM?
2) If so, what are the levels I should try to get to?
3) I have granualated chlorine (Calcium Hypochlorite) to hand and was going to add that - I think about 1kg of Chlorine to start with, but I've read that it's better to add liquid chlorine? No idea why, but happy to go and get hold of some if that's correct. But, how much should I be adding?

I'm a little confused because the CYA and Chorine level are so closely-related to each other. Thanks.


Denniswiseman
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Re: Question about SLAMing

Postby Denniswiseman » Fri 19 Jan, 2018 14:00

Hi stube40 and welcome
You say you haven't added any CYA but if you have been chlorinating with Trichlor or Dichlor you have been adding it
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm

CYA is the first thing to check before a slam
Read this about Slam first,with relation to Chlorine / CYA Chart and your Pool Levels
When slamming you are better of using liquid chlorine (sodium hypochlorite/ plain bleach)
Once your slam is done you can bring your CYA up to the recommended level
I wouldn't use cal hypo unless you want to raise your calcium level
The lower your CYA you will use less chlorine in your slam but having it low you risk an algae bloom
Pool Maths will work out just how much to add
BTW turn off your SWCG while running the slam
Teapot
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Re: Question about SLAMing

Postby Teapot » Fri 19 Jan, 2018 16:27

I think I read salt chlorinator, unless using stabilised pool salt then CYA will most like be low.

Calcium Hypo add calcium and therefore hardness to the water which may or may not be hard to start with. Liquid chlorine doesn't and mixes much faster into the water. You have a tester please give us the results.

Do we have to use SLAM? IT's shocking a pool.
Denniswiseman
Pool Industry Leader
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Posts: 2594
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Question about SLAMing

Postby Denniswiseman » Sat 20 Jan, 2018 03:02

Teapot wrote:I think I read salt chlorinator, unless using stabilised pool salt then CYA will most like be low.

Calcium Hypo add calcium and therefore hardness to the water which may or may not be hard to start with. Liquid chlorine doesn't and mixes much faster into the water. You have a tester please give us the results.

Do we have to use SLAM? IT's shocking a pool.

Hi John
My brain didn't register that a SWCG wouldn't be using Trichlor/Dichlor
SLAM stands for Shock Level and Maintain, a lot of people think shocking a pool is a one dose thing which it isn't (me included) untill they know better
A properly maintained pool shouldn't need a Slam/Shock
Teapot
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Posts: 1337
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Question about SLAMing

Postby Teapot » Sat 20 Jan, 2018 06:58

Lol it's the monosyllabic ism's I get bored of Lol

EDIT: Also when we go to talk about shocking a pool which is an industry std people won't understand. If we correctly describe the process Not a product but I get your point.

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